Quench, or quench and temper, metallurgical processes are widely used to harden, or harden and temper, a manufactured metal product such as steel pipe, to achieve desired metallurgical properties different from those for the starting material used to produce the metal product. Quenching is done after heating of the product, for example, by electric induction heating. Open spray quenching systems are one type of quench systems that can be used to accomplish the hardening and tempering of the metal product. When in-line quenching long, round products, such as pipes, bars or tubing, at production line speed, an important parameter that determines the material properties achieved by these processes is the metal cooling rate, which must generally be as fast as is possible to obtain the desired results. The cooling rate, in turn, is determined by the volume of quenchant used during the rapid cooling of a heated metal part. The traditional apparatus used to provide a high volume flow of water to the surface of a heated part is sometimes known as a quench barrel. The typical quench barrel is a large diameter, monolithic cylinder equipped with a multitude of holes through which quench media flows under medium pressure. Upon contact with the heated metal part, the quenchant provides the rapid cooling necessary to obtain a desired hardness. Also well known is the fixed position quench ring or slot quench. This apparatus is a hollow ring through which the part to be quenched passes. The apparatus contains a multitude of equally spaced holes or slots that act as nozzles for the quenching fluid. The slot quench is typically used in single part, small volume applications, such as induction hardening scanners.
Quenching systems must be capable of treating a range of product diameters. However, existing quench barrels and quench rings have a fixed inside diameter. When products having different diameters pass through these fixed diameter devices, the shape of the spray impinging on the product, the spray flow rate, and spray pressure change due to the difference in gap between the spray nozzles and the product. For existing quench systems when the spray is reflected from the product for a given nozzle, the reflected spray can interfere with the spray pattern of adjacent nozzles, and diminish or even destroy their effectiveness. The above limitations of existing quench systems can also cause expanding steam to form at the surface of the product to be quenched. This creates a thermal steam barrier that greatly reduces the rate of cooling of the product.
Further the small “pin hole” quench nozzles used to create the water jets in existing barrel quench systems limit the effective spray volumes and pressures that can be achieved.
Additionally since the product typically must move through the quench device both linearly and while rotating, the supporting conveyor rolls are skewed relative to the axis of travel of the product. This causes different diameter product to run on different centerlines through the conventional fixed geometry quench systems.
It is an object of the present invention to overcome the above limitations of existing spray quench systems.